Heart pacemaker Coloured chest Xray showing a surgicallyimplanted heart pacemaker bluered far right The pacemaker supplies electrical impulses along two wires redblue that lead to the heart orange lower right These impulses keep the heart beating regularly An irregular heartbeat cardiac arrhythmia is caused when the sinoatrial node the heart area that initiates the heartbeat malfunctions or when its impulses are being blocked heart block The chest bones lung areas and spinal column are also seen in this X ray